The present invention relates generally to the control of a defrost heater for a refrigerator and specifically to an adaptive control method and apparatus therefor.
It is known to provide a defrost heater to a refrigeration unit such as in a domestic refrigerator or freezer appliance. In conventional arrangements, the heater is cycled on the basis of electromechanical timers which accumulate time on the basis of compressor run time. When the timer accumulates a predetermined amount of compressor run time, the defrost heater initiates a defrost cycle, regardless of the current state of various refrigeration components and environment. This can lead to an inefficient use of energy.
According to an aspect of the present invention, a method for defrosting a household refrigeration appliance including a compressor and a refrigeration compartment having a door is provided. Said method comprises steps of:
setting a defrost interval (X) to an predetermined initial value (Xinitial);
initiating a defrost cycle after the defrost interval has elapsed and the compressor is not running;
after initiating said defrost cycle, terminating said defrost cycle as determined by a defrost termination thermostat, the period between initiating and terminating the defrost cycle being referred to as a defrost time (T);
decreasing said defrost interval (X) by a set amount if said defrost time (T) is greater than a set ideal maximum defrost time (Trange, max); and
increasing said defrost interval (X) by a set amount if said defrost time (T) is less than a set ideal minimum defrost time (Trange, min).